Two colorimetric methods for the assay of six nonsteroidal anti-inflammatory drugs in their pure and dosage forms

ABSTRACT

This paper described two new colorimetric methods for estimation of six nonsteroidal anti-inflammatory drugs; namely, piroxicam, tenoxicam, mefenamic acid, flufenamic acid, ibuprofen and ketoprofen in their pure forms and pharmaceutical preparations. The first method depends on scanning the azodyes resulting from the reaction of piroxicam and tenoxicam with diazonium salts of benzocaine, p-amino-N- methylbenzamide and sulfadiazine. The second procedure is based on colorimetric determination of the blue colored complexes yielded from the reaction of methylene blue with drugs under investigation. The different conditions for the proposed methods were studied. The methods have been applied for the analysis of pharmaceutical preparations containing these drugs and the results obtained were compared with those of pharmacopoeial or published methods. The methods are simple, precise and reproducible